Block 1 · Describe the Data

By the end of Block 1 you can…

✓Tell the difference between a variable and a constant, and name a variable's scale of measurement.
✓Build a frequency table and choose a bar chart vs. a histogram — and read a distribution's shape.
✓Compute the mean, median, and mode and know which one to trust when data are skewed.
✓Measure spread with the range, variance, and standard deviation.
✓Convert any score to a z-score and use the normal curve to find percentiles.

Test yourself

Block 1 Practice Test

12 multiple-choice questions spanning Units 1–5, with a few light calculations — just like the real thing. Practice only; never graded.

Sigma says: Don't memorize — reason. If the mean is bigger than the median, picture the long tail pulling it. Half of statistics is just drawing the picture in your head.